Copolyamides from m-and p-xylylene diamines and an aliphatic dibasic acid mixture

ABSTRACT

RANDOM COMPLYAMIDES OF (I) MIXTURE OF META-AND PARA-XYLYLENEDIAMINES WHEREIN THE META-FROM CONSISTTUTES AT LEAST 50 MOLE PERCENT BY WEIGHT WITH (II) A LONG CHAIN DIBASIC ACID CONTAINING 9 TO 12 CARBON ATOMS ARE USEFUL AS ENGINEERING PLASTICS, MIXTURES OF THE ACIDS MAY BE USED IN AN PROPORTION AND DIMER ACID MAY BE PRESENT UP TO 20 MOLE PERCENTAGE OF THE ACID CONSISTUENT, AS MUCH AS 20 MOLE PERCENT OF EITHER OR BOTH XYLYLENEDIAMINE MAY BE REPLACED BY PIPERAZINE.

United States Patent O 3,803,102 COPOLYAMIDES FROM m- AND p-XYLYLENEDIAMINES AND AN ALIPHATIC DIBASIC ACID MIXTURE Alfred Case Whiton, BlueBell, Pa., assignor to Pennwalt Corporation, Philadelphia, Pa. NoDrawing. Filed Aug. 21, 1972, Ser. No. 282,501 Int. Cl. C08g 20/20 US.Cl. 260-78 R 3 Claims ABSTRACT OF THE DISCLOSURE Random copolyamides of(i) mixtures of metaand para-xylylenediamines wherein the metaformconstitutes at least 50 mole percent by weight with (ii) a long chaindibasic acid containing 9 to 12 carbon atoms are useful as engineeringplastics; mixtures of the acids may be used in any proportion and dimeracid may be present up to 20 mole percentage of the acid constituent; asmuch as 20 mole percent of either or both xylylenediamine may bereplaced by piperazine.

BACKGROUND OF THE INVENTION The ability of xylylenediamine to formpolyamides with dibasic acids was recognized in the early Du 'Pontpatents on nylon and nylon production, such as US. 2,130,523; 2,130,947;2,130,948; 2,163,584; 2,163,636; 2,190,770; and 2,193,529. Many otherpatents have issued where specific xylylenediamines and dibasic acidsare suggested or taught as nylon forming materials, e.g. US. 2,766,221;2,773,902; 2,878,235; 2,916,475; 2,916,476; 2,987,506; 2,997,463;3,053,813; 3,145,133; 3,164,630; 3,200,183 and 3,439,025. No teaching ofthe highly useful and unexpected properties to be derived from thespecific copolyamides of the present invention is known however.

STATEMENT OF THE INVENTION The present invention provides a randomcopolyamide of repeating units of RZ- and Y--Z- wherein R is a member ofthe group (i) metaxylylenediamino and (ii) a mixture ofmetaxylylenediarnine and piperazino wherein metaxylylenediaminoconstitutes at least 80 mol percentage.

Y- is a member of the group of (i) paraxylylenediamino and (ii) amixture of paraxylylenediamino and piperazino whereinparaxylylenediamino constitutes at least 80 mol percentage,

-Z- is a member of the group of (i) and the dicarbonyl radical of dimeracid wherein 3,803,102 Patented Apr. 9, 1974 plastic. It is convenientlyprepared by conventional melt polymerization; in this process to obtainhigh molecular weight polymer from the dibasic acid-diamine salt, thereaction is carried out in two distinct stages, a prepolymer preparationstep and a finishing step. In the first step (preparing the prepolymer)the dibasic acid-diamine salt is heated slightly above its melting pointfor several hours in a closed vessel, to assure converting all thediamine contained in the salt into a low molecular weight polyamide (soit cannot be lost in this and subsequent operations). The finishing stepconsists of maintaining the molten prepolymer at an even highertemperature (260 C. or higher) for a few hours, frst at at atmosphericpressure (under nitrogen) and then under high vacuum. The purpose of thefinal stage is to remove from the system all the water formed in thecondensation of -NH,, and COOH groups to form CONH-- linkages, whichaids in driving the reaction to completion (to high molecular weightpolymer).

THE EXAMPLES The following examples are cited to illustrate theinvention; they are not intended to limit in any manner. In each exampleusing the mixed xylylenediamines (i.e. XDS), the mixture is one of molepercentage metaxylylenediamine and 30 mol percentage ofparaxylylenediamine. Dibasic acids which are straight chain andunsubstituted, are identified by a numeral corresponding to the numberof carbon atoms contained in the molecule. Piperazine, where present, isabbreviate Pip and D is used to indicate dimer acid. The propertiesreported in the examples and designated T T E and tensile modulus areall measured by standard ASTM methods using microtensile specimens.These properties may be defined as follows:

(a) T or yield tensile, is the stress at which the specimen exhibitspermanent deformation; it is a practical approximation of the elasticlimit of the material.

(b) T or tensile at break, is the ultimate strength of the materialsubjected to tensile loading; it is usually the maximum stress developedin the material in a tension test. Stress is the load on the specimendivided by the area through which it acts.

(0) E or elongation at break, is a measure of ductility of the materialdetermined in a tension test. It is the increase in length of thespecimen (measured after rupture) divided by the original length of thespecimen. Elongation is usually reported as a percent figure.

(d) Tensile modulus, included in Table II of Example 2, is a modulus ofelasticity in tension (or Youngs Modulus) of the specimen, and is anindication of the extent to which the material absorbs energy withoutpermanent deformation. Toughness as used in Table I of Example 1 is thenumerical product of T times E (or area beneath the stress-strain curveof the specimen in a tension test). This value denotes toughness of thematerial since it represents work-to-break or ability of the material toabsorb energy before fracture. Thus toughness in Table I is awork-to-break value, and tensile modulus in Table II is as stated above.

Example 1 Two 30 x 220 mm. cylindrical Pyrex glass tubes, fitted ontheir open ends with a precision ground high vacuum stocpcock, are eachcharged with 10.0 g. of pure, dry XDS/ 10 salt (previously prepared bymixing exactly equivalent amounts of sebacic acid and a blend of 70 molepercent metaxylylenedi-amine and 30 mole percent paraxylylenediamine;both the sebacic acid the diamine are dissolved in a minimum amount ofabsolute ethanol before mixing). The tubes are evacuated and purgedseveral times with nitrogen, finally are evacuated to approximately0.1-0.2 mm. and the stopcocks closed. The sealed tubes are then immersedin a bath of boiling liquid at 220 C. and held for five hours at thistemperature. The tubes are removed from the 220. C. bath after thislength 4 and can not be extruded through a Sieglatf-McKelvey rheometer.The MXD/lO sample shows poor load hearing properties at hightemperatures in a thermal mechanical analyzer. The XDS/l copolyamide ofthe present invention molds readily, is extrudable through the Siegoftime and the molten mass (prepolymer) allowed to laff-McKelvey rheometerand reglstered good ioad bearsolidify. 'ing properties at hightemperature on a thermal mechan- Prepolymer is removed from the twotubes used in the ical analyzer. first stage of the polymerization bybreaking the tubes, A series of random copolyamides prepared from thethe material is crushed into coarse granules and placed same XDS mixtureused above with acids and acid mixin a single 30 x 220 mm. cylindricalPyrex glass tube tures is prepared following the conventionalmelt-polymfitted on its open end with a straight section of 12 mm.erizat ion technique. The identity of the polymers and tubing. A sidearmis welded to the straight section of tubmeasured properties are reportedin Table II. Where a ing (for attachment to a vacuum pump) and a finecapilmixture of components (in addition to )GDS) is emlary is fittedinto the top of the polymer tube (for ployed, the mol proportion of'theconstituents of the bubbling nitrogen into the molten polymer). In thistube mixed component appears inparenthesis under the identity theprepolymer is remelted under nitrogen (in a liquid of the component.

TABLE II Tensile Wat-er Cryst Ty Tn En modulus 1711111 abs, M.P. Examplenumber Resin (p.s.i.) (p.s.i.) percent (p.s.i.) (dl./g.) percent C.)

2 XDS/10 10,540 8, 570 130 311x10 1.54 1.00 210 3 XDS/12 10,300 8,400130 2. 8 10 1.24 1.05 207 4 XD(S3/1%)+9 8,720 0, 950 180 27x10 1. 23 2.47 189 5 ling/125w 9,180 8,720 330 24x10 0. 90 3.00 174 0 zine /125th8,490 8, 450 210 27x10 1.24 1.03 200 7 XDi/ligl-D 0,410 0,200 130 1.9)10 1. 38 0. 86 187 8 xns -llii liz 8,760 7,010 110 2. 8x10 1.50 1.20 1939 XD%4+11)ip]12 6, 660 9,270 290 22x10 1.52 1.70 182 10 xDs+Pipl12+98,580 8, 450 180 2. 7x1m 1.72 1. as 186 11 XDS+PipI12+9 7,570 8,920 2402. 4x10 1.73 a. 170

bath boiling at 200 C.) and held at this stage for about THE REACTANTSone hour with nitrogen passing through the melt during The Xylylenediamines useful in preparing the copolyg? 3 dnvgn g .moltenamides of the present invention may be substituted in the mass y F g ito t e e an 535 3 aromatic ring by non-amide forming groups such aslower tents e mass is Cate or out out at alkyl, halide, nitro and thelike. The piperazine, when and 0.1 mm., then for three hours at 260 C.and 0.1 mm. i B th 1 h h d 1 used, may be simllarly substituted.

1s 130 W as i e lgh mo u at The acid moiety used to prepare thecopolyamide of the weight (evidenced by high viscos ty of the moltenmass), present invention may be any of decanedioic acid, i iffg gg g f iig lunder decanedioic acid, dodecanedioic acid, mixtures thereof g gg eg r0 Y om g and mixtures with dimer acid, the dimer acid when present ane Samp e (aPPmXPIate Y ma 6 Yea y constituting no more than 20 molpercentage of acids emfor phy81cal and mechanical tests. ployed.

E melt ge fi f grocedfne deslcnbeg abofve 15 Many equivalentmodifications of the present invenuse 0 PrePare 1g ecu at i P yaml es 0tion will be apparent to those skilled in the art without XDS/1O (re.the mixed xylylenediammes and sebacrc a dc t f th par ure rom elnventlve concept. ac1d), (b) MXD/ 10 (Le. metaxylylenediamme and b dPXD/IO 1 l What 1s claimed 18.

Se P g i' enediamme 1. A tough, high molecular weight random copolyamanSe i rloper 0 e tmg P0 ymers ide of repeating units of 70 mol percentageof R--Z-- are repor e m a e and 30 mol percentage of -Y--Z-- wherein -R-is TABLE I metaxylylenediamino, --Y-- is paraxylylenediamino and TB EBTau hness Z- is a mixture of (a) the radical Resin (dl./g.) (p.s.i.)percent p.51.) C.)

sesa- 223 as tti lfii a i H PXD wIIIIIII 11304 61940 120 0I8810 g and(b) the radical From the above it will be noted that tensile strength,elongation and toughness of the XDS/l0 sample, instead LL, of beingbetween the corresponding values of the MXD/ 10 and PSD/ 10 are higherin each instance. Furthermore, (a) constituting at least 50 molpercentage of said mixthe PXD/ 10 sample tends to decompose when moldedture.

5 6 2. The copolyamide of claim 1 wherein radical (a) FOREIGN PATENTSconstitutes 50 mol precentage of said mixture. 45 9590 4 970 Ja a 2 1'3N 3. The copolyamide of claim 1 wherein radical (a) 44/22,511 9/1969Japan 26078 R constitutes 75 mol percentage of said mixture. 1,142,4399/1957 France 26078 R 5 44/20,637 9/1969 Japan 26078 R References Cited836,127 6/ 1960 Great Britain 26078 R UNITED STATES PATENTS 573,1483/1959 Canada 26078 R Lum E. Primary Examiner 3,164,630 1/1965 Pietrusza26078 R G. MARSHALL, Assistant Examiner 3,649,602 3/1972 Tsuda 26078 R

